guitargeek

The bad news is that I made some miscalculations and have run into clearance issues, which means relocating my transformers...

To recap: I tried to build a single-ended EL84 powered amp using 5F2 iron. The 5F2 Princeton used a single 6V6 power tube, which puts out about the same power as an EL84, but is comfortable with higher voltages. This power transformer puts out WAY too much voltage for an EL84, so I was getting a condition called "red plate", which is where the plate (anode) glows cherry red. This shortens the lifespan of a tube to minutes! In an effort to bring the voltage down, I added a bucking transformer that decreased my mains voltage down to 105 volts AC, plus a swinging choke that brought my B+ down to something like 255 volts DC... which put 250 volts DC on the plate, exactly what an EL84 wants to be fed.



The problem was that it just didn't sound right. It sounded good, just not right. A choke in the power supply kinda chops the balls off of the tone by cutting out the low end. So while this wound up being a dead end, I consider it an interesting design exercise and a good learning experience.

I decided to switch to a 6V6 power tube, so off came the two extra transformers and the miniature 9-pin power tube socket in favor of an octal socket. This means I'm building a 5F1 Champ, sorta kinda more or less. I was almost done wiring that up when I decided to check how the chassis would fit in the cabinet and realized that I'd fucked up my calculations and that the transformers would hit the speaker! D'OH! So I had to pull both and relocate them:





STOP! BELLY RUB!



Okay, resume:





Now I just have to connect everything inside the chassis and make sure the transformers will happily co-exist that close together. I've got 'em oriented 90 degrees from each other, hopefully they won't induce hum if I can get my lead dress just right...



Wish me luck!